Phosphoric acid is a triprotic acid with the following pka values:

pka1=2.148, pka2=7.198, pka3=12.375

you wish to prepare 1.000 l of a 0.0500 m phosphate buffer at ph 7.540. to do this, you choose to mix the two salt forms involved in the second ionization, nah2po4 and na2hpo4, in a 1.000 l volumetric flask and add water to the mark. what mass of each salt will you add to the mixture?

mass nah2po4

mass na2hpo4

what other combination of phosphoric acid and/or its salts could be mixed to prepare this buffer? (check all that apply).

h3po4 and nah2po4

h3po4 and na2hpo4

h3po4 and na3hpo4

nah2po4 and na3po4

na2hpo4 and na3po4